Bearing for steel retainers



A. E. PETERS BEARING FOR STEEL RETAINERS Filed Sept. 8, 1932 IN VEN TOR.

' 197,5 ATTORNEY Patented Jan. 7, 1936 UNITED STATES PATENT OFFICE BEARING FOR STEEL RETAINERS Application September 8, 1932, Serial No. 632,120

1 Claim.

This invention relates to retainers for rock drill steels, but more particularly to a bearing for uncushioned retainers, as for instance the latch type, of which the retaining member is arranged within a slot in the front head and extends into the path of a protuberance, such as a collar on the drill steel or working implement to prevent ejection of the working implement from the rock drill whereby it is actuated.

6 One object of the invention is to provide a steel-retainer bearing which will avoid the undesirable condition of subjecting any of the parts, whereby the retainer is supported, to stresses other than those resulting from normal usage.

1?; Another object is to provide the retainer with cheaply renewable and readily replaceable bearmgs.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this specification and in which similar reference characters refer to similar parts,

Figure l is a side elevation in section of the front end of a percussive tool equipped with steelretainer bearings constructed in accordance with the practice of the invention, and

Figure 2 is a transverse view taken through Figure 1 on the line 2-2.

Referring more particularly to the drawing, the

invention is shown applied to a percussive tool A having a steel retainer B which may be substantially like that illustrated in United States Patent No. 1,712,239 granted to R. H. Wilhelm, May '7, 1929. V As is fully set forth in the aforesaid patent, the

steel retainer B may be held in the retaining position by a spring-pressed plunger and consists of a latch having a body portion C which lies within a slot D in a front head E of the percussive 40 tool. The retainer, moreover, has a handle F which normally seats against the side of the front head E. On the body portion C and on the inner portion thereof is a stop member G to act as an abutment for a collar H of aworking implement J which extends with its shank K into the front head E to receive the blows of a percussive element, such as a piston L.

In the form of percussive tool illustrated the cylinder 0, wherein the piston L reciprocates, is separated from the front head E by a front cylinder washer P and may be secured to the front head in any suitable manner, as for instance by the usual side bolts (not shown). In the present instance, the front cylinder washer P serves as a guide for an anvil block Q whereby the blowsof the hammer piston L are transmitted to the working implement J.

In accordance with the practice of the invention, the portions or walls R of the front head E which define the slot D are provided with coaxially aligned threaded apertures S which preferably extend entirely through the walls R. Disposed within the apertures S are bushings'T having external threads U for engagement with the threads in the aperture. 10

Within the bushings are recesses V to receive the ends of an imperforate pin W which extends through the retainer B to serve as a pivot therefor. The pin W is preferably freely rotatable within the recesses V and is somewhat l5 shorter than the distance between the bottoms of the recesses so that the pin W will also be capable of a slight degree of longitudinal movement with respect to the bushings and the retainer B. 20

On the outer ends of the bushings T are heads X which may be engaged for threading the bushings into the apertures S. The end surfaces Y of the heads X, adjacent the threaded portions of the bushings, seat against and fric- 25 tionally engage the outer surfaces of the walls R to retain the bushings fixedly in the walls. In the heads X of the bushings are apertures Z to constantly vent the recesses V and thus prevent the pin W from becoming air-locked. 30

The operation of the device is as follows: With the latch B and the working implement in the positions illustrated in the drawing, the stop member G extends into the path of the collar H of the working implement at a point 35 a sufiicient distance forwardly of the collar to permit of the free reciprocatory motion of the working implement imparted thereto by the piston L.

In the event, however, that a portion of the 40 work or rock is suddenly severed from the mass or if the leading end of the working implement V enters a void in the work, so that the longitudinal movement of the working implement with respect to the tool exceeds the normal distance 4 5 traveled by the working implement, the stop member G engages the collar H and thus prevents the ejection of the working implement from the front head.

' The shock of the severe impact of the working 50 implement against the stop member G is transmitted by theretainer to the pin Wand so to the front head. Upon the impact of the working implement against the stop member, should the collar H be slightly tilted with respect 65 to the stop member G as it frequently is in worn tools where excessive clearance exists between the working implement shank and the front head, the pin W will be shifted slightly in a longitudinal direction without imposing heavy strains upon any portion of the percussive tool. The only wear, therefore, to' which the tool will be subjected as a result of such movement of the pin will be confined to the pin itself and to the bearing members, each of which may be readily and cheaply replaced.

In practice, the present invention has been found to be highly efficient and to greatly extend the life of the parts whereby the retainer B is supported. As will be apparent from the foregoing description, the pin W is capable of free movement, either rotatively or longitudinally, and is, therefore, not rigidly connected to the parts whereby it is supported. Moreover, by providing disconnected bearing members for the opposite ends of the pin the walls R are not initially placed under a stress as is the case in structures where a pin, bolt or similar device is seated directly in the walls R and is itself provided withsecuring means that impose a .strain upon both the walls and such device.

As is well known, it has been found to be highly impractical to permit parts of a percussive tool, other than the percussive element, to have freedom of movement with respect to the elements .whereby they are encased or supported. In the case of a pivot member, such as the pin W, seated directly within the front head E it is, therefore, essential that it be secured afiixed to the front head, otherwise the surfaces upon which it seats will speedily become worn, and, in consequence, necessitate the replacement of the entire front head.

Equipped with bearings constructed in ac-- cord-ance with the invention the front head will be adequately protected against such wear as 5 might otherwise result from the vibratory movement of the pin W. The wear will be confined entirely to the bushings T which may be readily and cheaply replaced when unfit for service.

By threading the bushings into the walls R of the front head in the manner described the said walls R will be subjected only to the shock or impact of the collar H against the stop member G of the retainer and not to an additional strain imposed thereon by the latch pivot, as heretofore.

I claim:

A bearing for a retaining member, comprising a pair of supports spaced to receive the member therebetween, bushings threaded into the supports and having recesses opening from the inner ends of the bushings, an imperforate pivot pin for the retaining member extending with its ends into the recesses and being of less length than the distance between the outer ex- 26 tremities of the recesses to permit of endwise movement of the pin in the recesses, and shoulders on the bushings frictionally engaging the outer sides of the supports to retain the bushings fixedly in the supports and to prevent adjustment 30 of the bushings into binding engagement with the pin, said bushings having apertures affording constant communication between the recesses and the atmosphere.

ARTHUR E. PETERS. 

